How Generate table under database

i made plugin which auto generate database if not exist. same way i want to generate table under generated database. For Example

• I generate database with codes like ABCD.
• Now next i want generate DEF table under ABCD database.

I try these codes

function plugin_name_activation() {
require_once( ABSPATH . '/wp-admin/includes/upgrade.php' );
global $wpdb;
$db_table_name = $wpdb->prefix . 'table_name';
if( $wpdb->get_var( "SHOW TABLES LIKE '$db_table_name'" ) != $db_table_name ) {
if ( ! empty( $wpdb->charset ) )
$charset_collate = "DEFAULT CHARACTER SET $wpdb->charset";
if ( ! empty( $wpdb->collate ) )
$charset_collate .= " COLLATE $wpdb->collate";

$sql = "CREATE TABLE " . $db_table_name . " (
id bigint(20) UNSIGNED NOT NULL AUTO_INCREMENT,
type varchar(100) NOT NULL DEFAULT '',
extra longtext NOT NULL,
date_time datetime NOT NULL DEFAULT '0000-00-00 00:00:00',
PRIMARY KEY (id)
) $charset_collate;";
dbDelta( $sql );
}
}
register_activation_hook(__FILE__, 'plugin_name_activation');

Code (markup):

Link of these codes : web-profile.com.ua/wordpress/dev/create-table-on-plugin-activation/
But Not working these codes.

Please help. Help Appreciated .